1. Field of the Invention
The present invention relates to a display apparatus and a planar illumination apparatus.
2. Description of the Related Art
In recent years, to improve the effective contrast of liquid crystal display apparatuses, in particular, liquid crystal televisions, techniques have been available in which a screen is divided into a plurality of lighting areas and the brightness and darkness of a backlight are controlled according to the location of a lighting area and a display signal. The backlight is a planar illumination apparatus for use in liquid crystal display apparatuses. When the structure of the backlight is of a so-called “direct-lit type” in which light sources are disposed immediately below the display panel, it is difficult to achieve the slimming down of liquid crystal display apparatuses.
On the other hand, when the structure of the backlight is of a so-called “edge-lit type” in which a light guide plate made of a transparent plate and a light source around the light guide plate are disposed, slimming down is facilitated. For example, as shown in Japanese Patent Application Laid-Open No. 57-128383, the edge-lit type backlight is generally configured by a single light guide plate to obtain a single planar illumination light.